Friends, family and former teammates are still reeling from the suicide of Junior Seau. While much is still unclear over Seau’s motives, the leading suspicion is that any depression he had may have been a result of head trauma from the physical sport he played professionally for two decades. We’ll have that answer eventually now that Seau’s family has agreed to have his brain examined.

Gary Plummer, who spent four seasons as Seau’s teammate on the Chargers until 1993, thinks Seau suffered numerous concussions in his career, and the number he estimates is staggering.

“In the 1990s, I did a concussion seminar,” Plummer explained to the Contra Costa Times on Thursday. “They said a Grade 3 concussion meant you were knocked out, and a Grade 1 meant you were seeing stars after a hit, which made me burst out in laughter. As a middle linebacker in the NFL, if you don’t have five of these (Grade 1 effects) each game, you were inactive the next game.

“Junior played for 20 years. That’s five concussions a game, easily. How many in his career then? That’s over 1,500 concussions. I know that’s startling, but I know it’s true. I had over 1,000 in my 15 years. I felt the effects of it. I felt depression going on throughout my divorce. Junior went through it with his divorce.”

Even if you don’t agree with the way Plummer arrived at that figure, his comments do shed light on the frequency of head injuries with football players and the careless attitude they had for them. It’s important to note that Seau not once in his career was listed on the injury report for a concussion. Still doesn’t mean he never had one.

Seau played during a time when players could get away with playing through and not reporting concussions. It’s naive to believe Seau wasn’t guilty of it, too, especially when his ex-wife has confirmed it.